阅读说明：本技术 海水二氧化碳传感器高精度高效校准装置及其方法 (High-precision and high-efficiency calibration device and method for seawater carbon dioxide sensor ) 是由 郑旻辉 杨俊毅 潘建明 林燈科 廖丹宁 倪玮 于 2019-12-24 设计创作，主要内容包括：本发明公开了一种海水二氧化碳传感器高精度高效校准装置及其方法。该校准装置包括供气装置、校准器、储水器、控制盒和台式二氧化碳气体分析仪。本发明采用储水器和喷淋头等设计,具有较高的水气混合效率,能够保证校准试验的整体效率。而且本装置试验过程中全程无需开仓,通过控气三通阀、控水三通阀、控水阀等阀门切换即可实现放水、进水、鼓气、循环、检测等全部操作,可最大限度减小外界环境的干扰。本发明校准试验的基准值采用水气混合平衡以后校准器内空气中的二氧化碳浓度测定值,其测量原理与国际公认的走航二氧化碳连续观测系统一致,能够确保基准值的准确性。(The invention discloses a high-precision and high-efficiency calibration device and method for a seawater carbon dioxide sensor. The calibration device comprises a gas supply device, a calibrator, a water storage device, a control box and a desktop carbon dioxide gas analyzer. The invention adopts the design of the water storage device, the spray header and the like, has higher water-gas mixing efficiency and can ensure the overall efficiency of the calibration test. In addition, in the test process of the device, opening of the bin is not needed, and all operations such as water discharging, water inlet, air blowing, circulation, detection and the like can be realized through switching of valves such as an air control three-way valve, a water control valve and the like, so that the interference of the external environment can be reduced to the maximum extent. The reference value of the calibration test of the invention adopts the measured value of the concentration of carbon dioxide in the air in the calibrator after the water-air mixture is balanced, the measurement principle of the invention is consistent with the internationally recognized continuous observation system of the carbon dioxide during sailing, and the accuracy of the reference value can be ensured.)

1. A high-precision and high-efficiency calibrating device for a seawater carbon dioxide sensor is characterized by comprising a gas supply device, a calibrator (1), a water storage device (2), a control box (4) and a desk-top carbon dioxide gas analyzer (5); the gas supply device consists of a carbon dioxide supply device and a nitrogen supply device, gas is supplied into the calibrator (1) through a pipeline with a gas control three-way valve (10), and the gas control three-way valve (10) is a two-in one-out three-way valve; the calibrator (1) is a sealed container for placing a seawater carbon dioxide sensor (3) to be calibrated, the top of the calibrator is provided with a vent valve (6), a water inlet (7), a gas inlet (8) and a gas outlet (9), the gas inlet (8) is connected with an outlet of a gas control three-way valve (10) through a gas supply pipeline, and a gas outlet at the tail end of the gas supply pipeline extends below the liquid level of the calibrator (1); a water control three-way valve (11), a high-pressure water pump (12), an air pump (13), a dehumidifier (14) and a gas flowmeter (15) are arranged in the control box (4), and the water control three-way valve (11) is a two-in one-out three-way valve; the gas outlet (9) is sequentially connected with an air pump (13), a dehumidifier (14) and a gas flowmeter (15) through a gas outlet pipeline and then is communicated with a detection inlet of the desk type carbon dioxide gas analyzer (5), and a detection outlet of the desk type carbon dioxide gas analyzer (5) is connected with a first inlet of the gas control three-way valve (10) through the gas outlet pipeline; the water storage device (2) is arranged below the calibrator (1) and is communicated with the calibrator (1) through a water control valve (16); the carbon dioxide supply device comprises carbon dioxide storage equipment (17) and a first pressure reducing valve (19) which are sequentially connected through a carbon dioxide pipeline, and the nitrogen supply device comprises nitrogen storage equipment (18) and a second pressure reducing valve (20) which are sequentially connected through a nitrogen pipeline; the tail ends of the carbon dioxide pipeline and the nitrogen pipeline are converged into an air supply pipeline and then are connected to a second inlet of the air control three-way valve (10); the first inlet of the water control three-way valve (11) is connected with a calibrator water intake (21), the second inlet is connected with a water intake (22) of a water storage device, the outlet of the water control three-way valve is communicated to a calibrator water inlet (7) through a water pipe with a high-pressure water pump (12), and the water control three-way valve is connected with a spray head (23) for spraying the calibrator (1).

2. The high-precision and high-efficiency calibrating device for the seawater carbon dioxide sensor as claimed in claim 1, wherein a gas supply pipeline passing through the gas inlet (8) extends into the bottom of the inner cavity of the calibrator (1), and a gas outlet pipeline inlet passing out of the gas outlet (9) is positioned at the top of the inner cavity of the calibrator (1).

3. The high-precision and high-efficiency calibrating device for the seawater carbon dioxide sensor is characterized in that the calibrator water intake (21) is positioned at the bottom of the calibrator (1), and the water reservoir water intake (22) is positioned at the bottom of the water reservoir (2).

4. The high-precision and high-efficiency calibrating device for the seawater carbon dioxide sensor is characterized in that the calibrator (1) is a cylindrical shell made of organic glass, and the volume of the water reservoir (2) is 2/3 of the volume of the calibrator (1).

5. The high-precision and high-efficiency calibrating device for the seawater carbon dioxide sensor is characterized in that the seawater carbon dioxide sensor (3) to be calibrated is suspended and erected in the inner cavity of the calibrator (1) through a fixing frame.

6. The high-precision and high-efficiency calibration device for the seawater carbon dioxide sensor is characterized in that a water-gas mixed type fine atomization spray head is adopted as the spray head (23).

7. The high-precision high-efficiency calibration device for the seawater carbon dioxide sensor as claimed in claim 1, wherein the dehumidifier (14) is an electronic dehumidifier.

8. The high-precision and high-efficiency calibration device for the seawater carbon dioxide sensor as claimed in claim 1, wherein an air blowing sand nozzle (24) is installed at the tail end air outlet of the air supply pipeline.

9. The high-precision and high-efficiency calibration device for the seawater carbon dioxide sensor, according to claim 1, is characterized in that the carbon dioxide storage device (17) is a carbon dioxide gas cylinder; the nitrogen storage device (18) is a nitrogen cylinder.

10. A calibration method for a seawater carbon dioxide sensor by using the calibration device according to any one of claims 1 to 9, characterized by comprising the following steps:

s1: suspending a seawater carbon dioxide sensor (3) to be calibrated in an inner cavity of a calibrator (1) through a fixing frame, starting an air pump (13) and an electronic dehumidifier (14), adjusting a gas flowmeter (15) to enable the gas flow rate in a pipeline to meet the detection requirement of a table type carbon dioxide gas analyzer (5), and starting the seawater carbon dioxide sensor (3) and the table type carbon dioxide gas analyzer (5);

s2: opening the ventilation valve (6) and the water control valve (16), and closing the water control valve (16) after the water body in the calibrator (1) is completely discharged to the water storage device (2) under the action of gravity;

s3: adjusting the air inlet end of the air control three-way valve (10) to be communicated with the air supply pipeline;

s4: adjusting the opening degrees of a first pressure reducing valve (19) and a second pressure reducing valve (20), mixing carbon dioxide and nitrogen in an air supply pipeline according to a set flow ratio, introducing the mixture into a calibrator (1), dehumidifying part of air in the calibrator (1) along an air outlet pipeline through a dehumidifier (14), and then introducing the dehumidified air into a desk-type carbon dioxide gas analyzer (5);

s5: continuously measuring the concentration of carbon dioxide in the calibrator (1) by using a desktop carbon dioxide gas analyzer (5), and closing a first pressure reducing valve (19), a second pressure reducing valve (20) and a vent valve (6) when the measured value of the concentration reaches a set target value;

s6: adjusting the water inlet end of a water control three-way valve (11) to be communicated with a water inlet (22) of a water storage device, opening a high-pressure water pump (12) to spray water in the water storage device (2) from the top of a calibrator (1) in a spraying mode, adjusting the gas inlet end of a gas control three-way valve (10) to be communicated with a gas outlet pipeline, recycling gas flowing out of a detection outlet of a desktop carbon dioxide gas analyzer (5) to the tail end of the gas supply pipeline, and blowing the gas into a water body in the calibrator (1); after the seawater carbon dioxide sensor (3) to be calibrated is submerged by the liquid level of the water in the calibrator (1) and reaches a target position, adjusting the water inlet end of the water control three-way valve (11) to be communicated with a water intake (21) of the calibrator, and continuously and circularly spraying the water in the calibrator (1); in the circulation process of water and gas in the calibrator (1), continuously measuring the concentration of the gas carbon dioxide in the calibrator (1) by using a desk-top carbon dioxide gas analyzer (5), indicating that the water and gas mixture is balanced after the reading of the gas carbon dioxide gas analyzer is stable, respectively measuring the concentrations of the gas and the water carbon dioxide in the calibrator (1) by using the desk-top carbon dioxide gas analyzer (5) and a seawater carbon dioxide sensor (3), and respectively recording synchronous detection values of the gas and the water carbon dioxide;

s8: continuously repeating the steps S2-S7, and sequentially obtaining synchronous detection values of the desk-top carbon dioxide gas analyzer (5) and the seawater carbon dioxide sensor (3) after the carbon dioxide concentration in the calibrator (1) is balanced by water and gas mixing under different set target values;

s9: the measured value of the seawater carbon dioxide sensor (3) is calibrated by using each acquired synchronous detected value and using the measured value of the desk-top carbon dioxide gas analyzer (5) as a reference value.

Technical Field

The invention belongs to the field of sensor calibration, and particularly relates to a high-precision and high-efficiency calibration device and method for a seawater carbon dioxide sensor.

Background

Accurate determination of the partial pressure of carbon dioxide in seawater is key to revealing the role of the ocean in global climate change. In general, the means for obtaining the partial pressure of carbon dioxide in seawater include two methods: continuous observation of the carbon dioxide during navigation and long-term observation of the fixed-point in-situ carbon dioxide sensor. The seawater carbon dioxide sensor based on the osmotic membrane technology can obtain a large amount of in-situ data, and is widely applied to global climate change of offshore areas, oceans, polar regions and other sea areas and ocean acidification research of coral reefs and other sensitive areas. In the long-term use process of the carbon dioxide sensor in the field, data drift inevitably occurs due to the influences of biological contamination, loss of self components and the like, so that the sensor calibration is required to be carried out regularly.

Currently, high-precision and high-efficiency calibration of a seawater carbon dioxide sensor is a difficult problem in the international scientific community. The difficulty lies in three aspects: (1) the method is limited by the measurement principle, and compared with other sensors such as seawater dissolved oxygen, the currently available seawater carbon dioxide sensor has a larger volume, so that a larger water body environment is needed during calibration; (2) the solubility of carbon dioxide in water is not high, and the dissolution rate is slow, so that the change of the concentration of carbon dioxide in a large-volume water body is very difficult; (3) at present, high-precision desktop detection equipment and method capable of directly measuring the concentration of carbon dioxide in a water body do not exist, and great difficulty is brought to the measurement of a reference value of a seawater carbon dioxide calibration test.

In order to ensure the precision, the calibration device of the seawater carbon dioxide sensor which is commonly used internationally at present is very large in size. The carbon dioxide sensor and the continuous observation system for the carbon dioxide during the sailing are usually arranged in the same large water pool, so that the water bodies measured by the carbon dioxide sensor and the continuous observation system for the carbon dioxide during the sailing have the same carbon dioxide concentration. After the synchronous measurement data of the carbon dioxide sensor and the sensor are obtained, the measurement value of the international aerial carbon dioxide continuous observation system is used as a reference value, and the carbon dioxide sensor data is calibrated. Because a large amount of flowing water samples need to be extracted when the continuous observation system for the carbon dioxide is used for measurement, the method needs a huge test field in order to reduce the disturbance of the measurement process to the water body as much as possible. Although the accuracy is high, the calibration method has the serious defect that the partial pressure of carbon dioxide in the water body cannot be changed rapidly, and the carbon dioxide concentration value with more concentration gradients is difficult to obtain rapidly, so that the calibration efficiency is extremely low.

Therefore, an efficient high-precision calibration device for the seawater carbon dioxide sensor is established, timely and accurate calibration service is provided for the seawater carbon dioxide sensor in the using process of the seawater carbon dioxide sensor, and the important function of the seawater carbon dioxide sensor in ocean scientific research activities is better played.

Disclosure of Invention

The invention aims to solve the technical problems that the existing seawater carbon dioxide sensor calibration device is large in size and low in efficiency, and provides a high-efficiency high-precision seawater carbon dioxide sensor calibration device through improvement of the mixing efficiency of water carbon dioxide and reference value measurement.

The invention adopts the following specific technical scheme:

a high-precision and high-efficiency calibrating device for a seawater carbon dioxide sensor comprises a gas supply device, a calibrator, a water storage device, a control box and a desk-top carbon dioxide gas analyzer; the gas supply device consists of a carbon dioxide supply device and a nitrogen supply device, and supplies gas into the calibrator through a pipeline with a gas control three-way valve, wherein the gas control three-way valve is a two-in one-out three-way valve; the calibrator is a sealed container for placing a seawater carbon dioxide sensor to be calibrated, the top of the calibrator is provided with a vent valve, a water inlet, a gas inlet and a gas outlet, the gas inlet is connected with the outlet of a gas control three-way valve through a gas supply pipeline, and a gas outlet at the tail end of the gas supply pipeline extends below the liquid level of the calibrator; a water control three-way valve, a high-pressure water pump, an air pump, a dehumidifier and a gas flowmeter are arranged in the control box, and the water control three-way valve is a two-in one-out three-way valve; the gas outlet is connected with the gas pump, the dehumidifier and the gas flowmeter in sequence through a gas outlet pipeline and then communicated to the detection inlet of the desk type carbon dioxide gas analyzer, and the detection outlet of the desk type carbon dioxide gas analyzer is connected with the first inlet of the gas control three-way valve through the gas outlet pipeline; the water storage device is arranged below the calibrator and is communicated with the calibrator through a water control valve; the carbon dioxide supply device comprises carbon dioxide storage equipment and a first pressure reducing valve which are sequentially connected through a carbon dioxide pipeline, and the nitrogen supply device comprises nitrogen storage equipment and a second pressure reducing valve which are sequentially connected through a nitrogen pipeline; the tail ends of the carbon dioxide pipeline and the nitrogen pipeline are converged into an air supply pipeline and then are connected to a second inlet of the air control three-way valve; the first inlet of the water control three-way valve is connected with a water intake of the calibrator, the second inlet is connected with a water intake of the water storage device, and the outlet of the water control three-way valve is communicated to the water intake of the calibrator through a water pipe with a high-pressure water pump and is connected with a spray header for spraying the calibrator.

Preferably, the gas supply pipeline passing through the gas inlet extends into the bottom of the inner cavity of the calibrator, and the gas outlet pipeline passing through the gas outlet is positioned at the top of the inner cavity of the calibrator.

Preferably, the calibrator water intake is located at the calibrator bottom and the reservoir water intake is located at the reservoir bottom.

Preferably, the calibrator is a cylindrical housing made of plexiglass, and the reservoir volume is 2/3 of the calibrator volume.

Preferably, the seawater carbon dioxide sensor to be calibrated is suspended and erected in the inner cavity of the calibrator through a fixing frame.

Preferably, the spray header adopts a water-gas mixed type fine atomization spray head.

Preferably, the dehumidifier is an electronic dehumidifier.

Preferably, an air blowing sand nozzle is installed at an air outlet at the tail end of the air supply pipeline.

Preferably, the carbon dioxide storage device is a carbon dioxide gas cylinder; the nitrogen storage device is a nitrogen cylinder.

Another object of the present invention is to provide a calibration method for a seawater carbon dioxide sensor using the calibration apparatus according to any of the above aspects, comprising the following steps:

s1: suspending a seawater carbon dioxide sensor to be calibrated in an inner cavity of a calibrator through a fixing frame, starting an air pump and an electronic dehumidifier, adjusting a gas flowmeter to enable the gas flow rate in a pipeline to meet the detection requirement of a table-type carbon dioxide gas analyzer, and starting the seawater carbon dioxide sensor and the table-type carbon dioxide gas analyzer;

s2: opening the ventilation valve and the water control valve, and closing the water control valve after the water in the calibrator is completely drained to the water receiver under the action of gravity;

s3: adjusting the air inlet end of the air control three-way valve to be communicated with the air supply pipeline;

s4: adjusting the opening degrees of the first pressure reducing valve and the second pressure reducing valve to mix carbon dioxide and nitrogen in the gas supply pipeline according to a set flow ratio, introducing the mixture into a calibrator, and dehumidifying part of gas in the calibrator along the gas outlet pipeline by a dehumidifier and then introducing the dehumidified gas into a desk-top carbon dioxide gas analyzer;

s5: continuously measuring the concentration of carbon dioxide in the calibrator by using a desktop carbon dioxide gas analyzer, and closing the first pressure reducing valve, the second pressure reducing valve and the vent valve when the measured value of the concentration of carbon dioxide reaches a set target value;

s6: adjusting the water inlet end of the water control three-way valve to be communicated with a water intake of a water storage device, opening a high-pressure water pump to spray water in the water storage device from the top of the calibrator in a spraying mode, adjusting the gas inlet end of the gas control three-way valve to be communicated with the gas outlet pipeline, recycling gas flowing out of a detection outlet of the desk-top carbon dioxide gas analyzer to the tail end of the gas supply pipeline, and blowing the gas into a water body in the calibrator; after the liquid level of the water in the calibrator submerges the seawater carbon dioxide sensor to be calibrated and reaches a target position, adjusting the water inlet end of the water control three-way valve to be communicated with a water intake of the calibrator, and continuously and circularly spraying the water in the calibrator; in the circulation process of water and gas in the calibrator, continuously measuring the concentration of the gas carbon dioxide in the calibrator by using a desk-top carbon dioxide gas analyzer, indicating that the water and gas mixture is balanced after the reading of the gas carbon dioxide gas analyzer is stable, respectively measuring the concentrations of the gas and the water carbon dioxide in the calibrator by using the desk-top carbon dioxide gas analyzer and a seawater carbon dioxide sensor, and respectively recording synchronous detection values of the gas and the water carbon dioxide;

s8: continuously repeating the steps S2-S7, and sequentially obtaining synchronous detection values of the desk-top carbon dioxide gas analyzer and the seawater carbon dioxide sensor after the carbon dioxide concentration in the calibrator is balanced in water-gas mixing under different set target values;

s9: and calibrating the measured value of the seawater carbon dioxide sensor by using the obtained synchronous detected values and taking the measured value of the desk-top carbon dioxide gas analyzer as a reference value.

Compared with the prior art, the invention has the following beneficial effects:

according to the high-precision and high-efficiency calibrating device for the seawater carbon dioxide sensor, the calibrator has a large volume, and the size of the calibrator can meet the calibration requirements of all existing seawater carbon dioxide sensors at home and abroad; by adopting the design of the water storage device, the fine atomization nozzle and the like, the device has higher water-gas mixing efficiency, and can ensure the overall efficiency of a calibration test; the whole test process does not need opening the bin, and all operations such as water discharging, water feeding, air blowing, circulation, detection and the like can be realized by switching valves such as an air control three-way valve, a water control valve and the like, so that the interference of the external environment can be reduced to the maximum extent; the reference value of the calibration test is the carbon dioxide concentration measurement value in the air in the calibrator after the water and the air are mixed and balanced, the measurement principle of the calibration test is consistent with that of an internationally recognized continuous observation system for the carbon dioxide during sailing, and the accuracy of the reference value can be ensured.

Drawings

FIG. 1 is a schematic structural diagram of a high-precision and high-efficiency calibration device for a seawater carbon dioxide sensor according to the invention;

FIG. 2 is a schematic diagram of the present apparatus in use for calibrating a carbon dioxide sensor in a body of water;

in the figure: the device comprises a calibrator 1, a water receiver 2, a seawater carbon dioxide sensor 3 to be calibrated, a control box 4, a table type carbon dioxide gas analyzer 5, a vent valve 6, a water inlet 7, a gas inlet 8, a gas outlet 9, a gas control three-way valve 10, a water control three-way valve 11, a high-pressure water pump 12, an air pump 13, a dehumidifier 14, a gas flowmeter 15, a water control valve 16, a carbon dioxide storage device 17, a nitrogen storage device 18, a first pressure reducing valve 19, a second pressure reducing valve 20, a calibrator water intake 21, a water receiver water intake 22, a spray header 23 and an air blowing sand nozzle 24.

Detailed Description

The invention will be further elucidated and described with reference to the drawings and the detailed description. The technical features of the embodiments of the present invention can be combined correspondingly without mutual conflict.

As shown in fig. 1, a high-precision and high-efficiency calibration device for a seawater carbon dioxide sensor provided in an embodiment of the present invention includes a gas supply device, a calibrator 1, a water reservoir 2, a seawater carbon dioxide sensor 3 to be calibrated, a control box 4, and a desktop carbon dioxide gas analyzer 5. The calibrator 1 is a main body for water-gas mixing and sensor calibration, the gas supply device is composed of a carbon dioxide supply device and a nitrogen supply device, and gas is supplied into the calibrator 1 through a pipeline with a gas control three-way valve 10 to adjust the concentration of carbon dioxide in the calibrator 1. Wherein, the gas control three-way valve 10 is a two-in one-out three-way valve, the gas inlet end of the gas control three-way valve is provided with two gas inlets, the gas outlet end is provided with only one gas outlet, and one of the two gas inlets is communicated with the gas outlet;

calibrator 1 is a sealed container, and the shape is cylindrical casing, adopts the organic glass material to make to observe the internal state. The seawater carbon dioxide sensor 3 to be calibrated is suspended in the inner cavity of the calibrator 1 through a fixing frame, 1 sensor can be calibrated independently in the calibrator 1, and a plurality of sensors can also be calibrated simultaneously. The top of the calibrator 1 is provided with a vent valve 6, a water inlet 7, a gas inlet 8 and a gas outlet 9, and the rest parts of the calibrator 1 except the openings are kept closed. The vent valve 6 can be controlled to open and close according to the test requirement, and is communicated with the external atmosphere when opened so as to release the internal pressure. The gas inlet 8 is connected with an outlet of the gas control three-way valve 10 through a gas supply pipeline, and a gas outlet at the tail end of the gas supply pipeline extends below the liquid level of the calibrator 1 and is used for blowing gas conveyed in the gas supply pipeline into a water body to realize the water-gas exchange of carbon dioxide gas.

The control box 4 is a box body for placing various control devices, and a water control three-way valve 11, a high-pressure water pump 12, an air pump 13, a dehumidifier 14 and a gas flow meter 15 are placed in the box body. The water control three-way valve 11 is a two-in one-out three-way valve, the water inlet end of the water control three-way valve is also provided with two water inlets, the water outlet end of the water control three-way valve is also provided with only one water outlet, and one of the two water inlets is communicated with the water outlet. The gas outlet 9 is connected with the air pump 13, the dehumidifier 14 and the gas flowmeter 15 in sequence by a gas outlet pipeline and then leads to the detection inlet of the desk-top carbon dioxide gas analyzer 5, and the detection outlet of the desk-top carbon dioxide gas analyzer 5 is connected with the first inlet of the gas control three-way valve 10 by a gas outlet pipeline.

The water storage device 2 is arranged below the calibrator 1 and is communicated with the calibrator 1 through a water control valve 16. The function of the water control valve 16 is to control whether the water in the calibrator 1 can flow into the water reservoir 2, when the water control valve 16 is opened, the flow path is through, the water in the calibrator 1 can flow into the water reservoir 2 under the gravity for storage, and when the water control valve 16 is closed, the flow cannot flow. Thus, to ensure that the reservoir 2 is sufficient to store the water flowing down the calibrator 1, the volume of the reservoir 2 should be 2/3 of the volume of the calibrator 1, since the water in the calibrator 1 is not filled and a certain upper space needs to be reserved.

The carbon dioxide supply means includes a carbon dioxide storage device 17 and a first pressure reducing valve 19 which are connected in sequence by a carbon dioxide line, and the nitrogen supply means includes a nitrogen storage device 18 and a second pressure reducing valve 20 which are connected in sequence by a nitrogen line. The tail ends of the carbon dioxide pipeline and the nitrogen pipeline are converged into an air supply pipeline and then connected to a second inlet of the air control three-way valve 10. The first pressure reducing valve 19 and the second pressure reducing valve 20 can adjust the opening degree, and accordingly the air flow of the branch is controlled respectively. By adjusting the opening degrees of the first pressure reducing valve 19 and the second pressure reducing valve 20, the mixing ratio of the carbon dioxide gas and the nitrogen gas in the gas supply line can be changed, and the concentration of the carbon dioxide gas in the gas blown into the calibrator 1 can be further changed.

In addition, because only one of the two inlets of the three-way valve 10 can be connected, the source of the gas blown into the calibrator 1 can be adjusted by changing the connection direction of the gas inlet end of the three-way valve 10. When it is necessary to change the gas concentration in the calibrator 1, the gas concentration in the calibrator 1 can be changed by using a gas of a specific concentration in the gas supply line by adjusting the gas inlet port to communicate with the gas supply line. And when the gas concentration in the calibrator 1 need not to be changed, then can be through adjusting the inlet end to the intercommunication opposite side, communicate the gas outlet pipe way promptly, utilize the effect of air pump 13 to make the gas in the calibrator 1 constantly circulate, utilize calibrator 1 self inside gas to carry out the gas blowing, and then realize that the aqueous vapor mixes.

In addition, the purpose of the present invention of having the reservoir 2 below the calibrator 1 is to enable water to be drawn directly from the reservoir 2 each time for initial water-air mixing, without the need for an initial self-circulation with the water inside the calibrator 1. The method for changing water can greatly improve the water-gas mixing efficiency. For this purpose, the water-controlling three-way valve 11 is used for switching, the first inlet of the water-controlling three-way valve 11 is connected with the calibrator water intake 21, the second inlet is connected with the water intake 22 of the water storage device, the outlet of the water-controlling three-way valve is communicated with the calibrator water intake 7 through a water pipe with the high-pressure water pump 12, and the circulating water source can be changed through the switching of the inlet ends. To ensure smooth and convenient water intake, the calibrator water intake 21 should open at the bottom of the side of the calibrator 1 and the reservoir water intake 22 should open at the bottom of the side of the reservoir 2.

In addition, after the water pipe circulating from the high pressure water pump 12 passes through the calibrator water inlet 7 and enters the inside of the calibrator 1, a shower head 23 for spraying the calibrator 1 needs to be connected. In this embodiment, in order to improve the mixing efficiency, the spray head 23 employs a water-gas mixed type fine atomization nozzle to atomize the spray water, thereby increasing the water-gas contact surface area and prolonging the contact time. Similarly, in order to ensure that the gas-water contact time and mixing efficiency are improved as much as possible, the gas supply line passing through the gas inlet 8 extends into the bottom of the inner cavity of the calibrator 1, and the gas outlet line passing through the gas outlet 9 has an inlet at the top of the inner cavity of the calibrator 1. An air blowing sand nozzle 24 is arranged at an air outlet at the tail end of the air supply pipeline so as to disperse bubbles as much as possible and improve the mass transfer efficiency.

In addition, the dehumidifier 14 in the present embodiment is an electronic dehumidifier, and functions to meet the requirement of inlet air drying of the table-type carbon dioxide gas analyzer 5. The carbon dioxide storage device 17 is a carbon dioxide gas cylinder, and the nitrogen storage device 18 is a nitrogen cylinder. Of course, other high pressure gas storage devices may be used as long as the gas storage function is achieved. In addition, the connection between the air pipe and the interface is provided with sealing. For the air tightness inside the calibrator 1, the connections between the respective air pipes, water pipes and the respective interfaces on the housing should have a seal.

The operation method of the high-precision and high-efficiency calibration device for the seawater carbon dioxide sensor according to the present invention is further described below by using a seawater carbon dioxide sensor 3 and a desktop carbon dioxide gas analyzer 5 as an example. In the calibration process of the seawater carbon dioxide sensor 3, the key steps are to set a plurality of target carbon dioxide gas concentrations according to the calibration requirements, when a certain target carbon dioxide gas concentration is reached in the calibrator 1, the water body and the gas are subjected to sufficient water-gas exchange, and then the calibration of the seawater carbon dioxide sensor is carried out based on the water body reaching balance.

In the present embodiment, the target carbon dioxide gas concentration required for calibration is 800, 700, 600, 500, 400, 300, 200 μ atm in this order. According to the preset target, the calibration method of the seawater carbon dioxide sensor based on the calibration device specifically comprises the following steps:

(1) the connection of all parts of the device is completed, and the seawater carbon dioxide sensor 3 to be calibrated is suspended and erected in the inner cavity of the calibrator 1 through a fixing frame (as shown in figure 2). The air pump 13 and the electronic dehumidifier 14 are started, the gas flow meter 15 is adjusted to enable the flow rate of gas in the pipeline to meet the detection requirement of the table-type carbon dioxide gas analyzer 5, test water meeting the calibration dosage is injected into the calibrator 1 in advance, the seawater carbon dioxide sensor 3 and the table-type carbon dioxide gas analyzer 5 are started, and the operation program is started.

(2) And (3) opening the ventilation valve 6 and the water control valve 16, and closing the water control valve 16 after the water in the calibrator 1 is completely drained to the water storage device 2 under the action of gravity.

(3) The air inlet end of the air control three-way valve 10 is adjusted to be communicated with the air supply pipeline.

(4) According to the relation between the concentration of the carbon dioxide in the calibrator 1 and a control target value, opening flows of a first reducing valve 19 and a second reducing valve 20 are adjusted, so that the carbon dioxide and nitrogen in an air supply pipeline are mixed according to a set flow proportion to obtain a proper concentration of the carbon dioxide, and the proper concentration of the carbon dioxide is introduced into the calibrator 1; part of the gas in the calibrator 1 is dehumidified by the dehumidifier 14 along the gas outlet pipeline and enters the bench-type carbon dioxide gas analyzer 5, and the excess gas is discharged through the vent valve 6. When the opening degree of the valve is adjusted in this step, if the concentration of carbon dioxide in the calibrator 1 is higher than the control target value, the opening degree of the second reducing valve 20 is increased, the opening degree of the first reducing valve 19 is decreased, and the concentration of carbon dioxide in the gas supply pipeline is further decreased; if the carbon dioxide concentration in the calibrator 1 is lower than the control target value, the opening degree of the second pressure reducing valve 20 is decreased, the opening degree of the first pressure reducing valve 19 is increased, and the carbon dioxide concentration in the gas supply line is increased.

(5) The carbon dioxide concentration in the calibrator 1 is continuously measured by using the desk-top carbon dioxide gas analyzer 5, and when the measured value reaches 800 μ atm, the first pressure reducing valve 19, the second pressure reducing valve 20, and the vent valve 6 are closed, and the gas supply to the gas supply line is stopped.

(6) The water inlet end of the water control three-way valve 11 is adjusted to be communicated with a water intake 22 of the water storage device, the high-pressure water pump 12 is opened to spray water in the water storage device 2 from the top of the calibrator 1 in a spraying mode, the air inlet end of the air control three-way valve 10 is adjusted to be communicated with an air outlet pipeline of a detection outlet of the desk-top carbon dioxide gas analyzer 5, gas flowing out of the detection outlet of the desk-top carbon dioxide gas analyzer 5 is recycled to the tail end of the air supply pipeline, and the gas is blown into the water body in the calibrator 1. After the water level of the seawater carbon dioxide sensor 3 to be calibrated in the calibrator 1 reaches a target position (the specific height is set according to the test requirement), the water inlet end of the water control three-way valve 11 is adjusted to be communicated with the water intake 21 of the calibrator, so that the water in the calibrator 1 is continuously and circularly sprayed. In the process, the steam is fully contacted and exchanged through the actions of the gas blowing in the gas blowing sand nozzle 24 and the spraying of the spray head 23, and the concentration of the carbon dioxide of the two phases tends to be balanced gradually. Therefore, in the circulation process of the water and the gas in the calibrator 1, the desktop carbon dioxide gas analyzer 5 is used for continuously measuring the concentration of the gas carbon dioxide in the calibrator 1, the balance of the water and the gas is indicated after the reading of the gas carbon dioxide gas analyzer is stable, the desktop carbon dioxide gas analyzer 5 and the seawater carbon dioxide sensor 3 are used for respectively measuring the concentrations of the gas and the water carbon dioxide in the calibrator 1, and the synchronous detection values are respectively recorded.

(7) The steps (2) to (6) are repeated, but each time the steps are repeated, the opening degrees of the two pressure reducing valves need to be changed according to a preset target carbon dioxide concentration value, and the carbon dioxide concentration in the calibrator 1 needs to be adjusted. Thus, in the present embodiment, the synchronous detection values of the bench-type carbon dioxide analyzer 5 and the seawater carbon dioxide sensor 3 after the water-gas mixture balance under the conditions of the carbon dioxide concentration in the calibrator 1 of 700, 600, 500, 400, 300, and 200 μ atm can be obtained in sequence;

(8) by using all the obtained synchronous detection values, the measurement value of the seawater carbon dioxide sensor 3 can be calibrated by using the measurement value of the desk-top carbon dioxide gas analyzer 5 as a reference value.

Therefore, in the operation process of the device, the combination mode of air blowing, spraying and water changing is actually adopted, the water-air exchange balance can be quickly realized, and the calibration speed of the sensor is accelerated. To illustrate the improvement in water-air mixing efficiency of the present apparatus over the prior art apparatus, a set of comparative experiments were conducted. The following three water-gas mixing operation modes are characterized respectively by gas blowing, spraying and water changing in the start-stop device:

A. air blowing only: i.e. each time it is started, the water in calibrator 1 is not drained to reservoir 2, but is stored completely in calibrator 1, circulating itself. Meanwhile, in the water-gas exchange process, the operation of the water pump in the step (6) is stopped, spraying is not carried out, and only the air blowing mode of the air blowing sand nozzle 24 is adopted.

B. Air blowing and spraying: i.e. each time it is started, the water in calibrator 1 is not drained to reservoir 2, but is stored completely in calibrator 1, circulating itself. But both spraying and blowing are performed during the water-gas exchange process.

C. Air blowing, spraying and water changing: that is, with the above-described adjustment method of the present invention, every time it is started, the water in the calibrator 1 is discharged to the water reservoir 2, and then it is filled into the mixer 1 by the water pump, after which the internal circulation is performed. Meanwhile, in the water-gas exchange process, spraying and air blowing are carried out.

The calibration of the carbon dioxide sensor is taken as an example in the three tests, the initial carbon dioxide concentrations in the water body and the air in the calibrator 1 are approximately the same, the water-air mixing efficiency is judged by comparing the time required for reaching the equilibrium after mixing, and the specific results are shown in table 1. The results show that the device provided by the invention has the shortest time for achieving the balance by adopting the method of air blowing, spraying and water changing, and the device is remarkably improved in the aspect of water-air mixing efficiency compared with the existing device. The method of discharging all the water bodies in the calibrator 1 to the water receiver 2 and then pumping the water bodies into the calibrator 1 again each time can ensure that the water bodies pumped out from the water receiver 2 exchange with gas at the maximum mass transfer speed in the calibrator 1, and avoids the problem that the water bodies which have completed water-gas exchange are mixed with other water bodies which have not been exchanged so as to reduce the mass transfer efficiency.

TABLE 1 comparison of the Water-air mixing efficiency of this device with the existing device

The above-described embodiments are merely preferred embodiments of the present invention, which should not be construed as limiting the invention. Various changes and modifications may be made by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present invention. Therefore, the technical scheme obtained by adopting the mode of equivalent replacement or equivalent transformation is within the protection scope of the invention.